The present invention relates to removable digital media. More particularly, the present invention is directed to a method and apparatus for converting the format of data transferred between a removable digital medium and a host.
A variety of add-on or removable cards and modules for use in digital systems such as personal computers, personal digital assistants (PDAs), digital cameras, cellular phones, and pagers, are becoming widely used. For example, many digital devices are arranged to work with removable digital storage cards or media. Removable storage media usually employ flash memory. Flash memory is non-volatile and is ideal for mobile or hand-held devices because of its small size, low power consumption, high speed and superior reliability.
The Personal Computer Memory Card Interface Association (PCMCIA) has established an interface standard for removable digital storage media. It is known as the PCMCIA interface or PC card standard. It has become the standard for other removable media such as modems and hard drives. There are two main flash memory architectures that meet the PCMCIA interface standard. These are the Advanced Technology Attachment (ATA) flash and Linear flash. The ATA flash includes a processor in addition to memory, and emulates a hard disk drive. Linear flash relies on the processing ability of the host device.
The PCMCIA standard is often not suitable for small portable devices. Therefore, a number of removable digital media have been developed having smaller form factors than the standard PC card. Some examples of these smaller media include CompactFlash, Miniature Card, Solid State Floppy Disk Card (SSFDC) or SmartMedia, and MultiMedia Card. Most of these new, smaller cards, are provided with an adapter to conform to the PCMCIA standard to fit into devices having card slots arranged to accept PCMCIA standard cards.
Some of the advantages contributing to the recent success of removable digital media include system flexibility, portability and ease of data transfer from one host to another. However, the ability to transfer data from one host to another is limited by compatibility constraints. More particularly, data may be stored on a removable digital medium in any one of a number of data formats. Therefore, a host attempting to access information stored on a removable storage medium must support a data format that is compatible with the format of the stored data. Otherwise, the host will be unable to access the stored data. As digital technology evolves, it is likely that there will be a large number of devices that may not be compatible with new data formats. This is particularly true for portable devices or simple devices that are not usually upgraded to be compatible with new technology. Therefore, those devices that are not upgraded to be compatible with evolving digital technology will not be able to take advantage of the benefits associated with the evolving technology. Moreover, the advantage of using removable digital media to transfer data from one host to another will likely be increasingly impeded by compatibility constraints.
Therefore, there is a need for a method and apparatus for converting data, transferred between a host and a removable digital medium, from a particular format to a format that is compatible with the host, or to a format selected by the host. More particularly, a removable digital medium that supports a plurality of data formats and provides for the conversion of data from a particular format to a format that is compatible with a host device in which it is connected is needed. In addition, a removable digital medium that supports a plurality of data formats and provides for the conversion of data from a particular format to a format that is selected by a host device in which it is connected is needed.
The deficiencies and limitations of the prior art are overcome by the present invention which provides a removable digital medium supporting automatic format conversion. More particularly, the removable digital medium according to the present invention supports a plurality of data formats and converts data transferred between a host and the removable digital medium to another format that is supported by the removable storage medium and selected by the host. The removable digital medium according to the present invention is provided with a directory structure for accomplishing the automatic format conversion. The directory identifies the possible formats that are supported by the removable digital medium. In this manner, the invention enables existing or legacy consumer electronic devices to adapt to improvements in technology, such as improvements in image compression and file formats. In addition, the invention enables the advantage of removable digital media to transfer data from one host to another to be more fully realized.
According to another aspect of the present invention, a method of converting the data format of data transferred between a host and a removable digital medium to a format that is compatible with the host is provided.
In yet another aspect of the present invention, a method of converting the data format of data transferred between a host and a removable digital medium to a data format selected by the host, from a plurality of data formats supported by the removable digital medium.
According to another aspect of the invention, an improved removable digital medium for converting the data format of data transferred between a host and the removable digital medium to a format that is compatible with the host is provided.
According to yet another aspect of the present invention, an improved removable digital medium that supports a plurality of data formats and that converts the data format of data transferred between a host and the removable digital medium to a data format selected by the host is provided.
These and other objects and features of the present invention will be apparent upon consideration of the following detailed description of preferred embodiments thereof, presented in connection with the following drawings in which like reference numerals identify like elements throughout.